Apparatus for buffing bumper bars



E S R E V E R 3 Sheets-Sheet 1 f. a 0 2 h 4 3 3, y a W w J w 5 5 u A 5 2MP a? a a; u x 3 m n M x 3 Fzg- 1 T. E. ROBINSON ETAL APPARATUS FOR BUFFING BUMPER BARS CD/g LOAD

July 25, 1950 Filed April 28, 1947 UNLOAD Jul 25, 1950 T. E. ROBINSON ETAL APPARATUS FOR BUFF ING BUMPER BARS Filed April 28, 1947 5 Sheets-Sheet 2 Patented July 25, 1950 UNITED. STATES PATENT OFFICE 2,516,256

APPARATUS FOR BUFFING BUMPER BARS Thomas E. Robinson, Grosse Pointe, and Frank H. Hartlep, Detroit, Mich, 'a'ssignoi's to Houdaille-Hersh'ey Corporation, Detroit, Mich, a

corporation of Michigan Application April 28, 1947, Serial No. 744.344 1 claim. (01. 51-417) This invention relates to a machine for effecting the polishing or boiling of irregularly contoured surfaces. This machine has particular application to the polishing or bufiing oi arcuate end portions of bumper bars for modern automotive vehicles.

The current trends in automotive design have resulted in a one-piece bumper construction having arcuate. endportions of considerable extent and departure from the central portion of the bumper. When such bumpers are assembled on a car, the central portion extends across the front of the car substantially parallel thereto, while the arcuate end portions extend generally around each side of the car and project a substantial distance rearwardly.

The manufacture of bumper bars of such configuration has heretofore been more expensive and time consuming through the lack of suitable machines for efi'ectively polishing the curved and portions of the bumper bars. Suchcurved portions generally do not constitute circular segments, but are of non-circular arcuate configuration and hence cannot be conveniently polished on a machine of the conventional rotary table type. The problem is further complicated by the fact that most of such bumper bars have non-concentric cross sections, i. e., non-concentric about a medial plane passing through the length axis of the bar.

Accordingly, it is an object of this invention to provide an improved machine for effecting the polishing or buffing of irregularly contoured articles, and particularly, for polishing the arouate end portions of modern bumper bars for auto motive vehicles.

A particular object of this invention is to pro vide a; polishing machine for rapidly and economically effecting the polishing of the arcuate end portions of bumper bars in which the only manual attention required is the loading of the bumper bars onto a conveyor portion of the machine at a loading station, the reversal of the bumper bars end for end at an intermediate sta tion, and the unloading of the bumper bars from the bumper conveyor at the end of the polishing operation.

A further object of this invention is to provide a machine for polishing the curved end portions of bumper bars wherein clamps are provided on an endless conveyor for detachably securing a bumper bar thereon in such position that one of the arcuate end portions is disposed in general alignment with the. direction of movement of the conveyor, whereupon the. polishing of such one 2 arcuate end portion may be accomplished by re;- tating polishing Wheels aisposea along the path of movement or the conveyor.

Still another object of this invention is to provide an improved mounting for so honing bumper bars on the eonveyor'or a polis n'g machine which will automatically compensate for changes in spatial position of the a one end portions of such bumper bai vvheii ieve sod and for end on the conveyor, which may result dii to the fact that the bumper bars are or nonconcentric cross sectional configuration.

The specific nature of the invention as well as other objects and advantag s thereof willb'eciiiiie apparent to this skilled" in me n from the idl lowing detailed description or the annexed s eets of drawings which, by way of preferred example only, prostrate one specific embodiment of t e invention. On the drawings: 1 n I Figure '1 is a schematic viewinustr atiog the path of 'a conve or and operatingstations' em ployed in a machine embodying this invent on for transporting'the bumper oars past a plurality of rotating polishing Wheels; I Figure 2 is an elevatiohal view' or a portion of the conveyor or a machine embodying this iii vention showing the bumper bars positioned thereon; I v

Figure 3 use transverse sectional taken onthe mane III--III Of Figure 2 p o Figure 4 is an enlarged cale, front elevatiohal view of one of the clamping elements endorse for mounting the bumper bars on the conveyor: and v v Figure 5 is a side devotional view of Figure- 4, and shows in addition the position or a Bumper bar when secured by the clamps.

s snown'on the drawings; f

As best s own in Figures 2 and 3, a machine embodying this nvention comprises a enerally reotang'mar, block-like time structure llvvliicli ma be onven ently. fabricated by wading riveting together of structural beanrmefiiters, Silh frain construction includes a pliifality of spaced uprliglit. members too which are rigidly secured to and interconnected by generally horif zontal base members lb. Adjacrittlie top it upright members led, a paii of angle iiienibrs Z are respectively mounted vertically spaced relationship. to define therebetwlen a. track- 12d. Adjacent the lower portions of uprights t tle a pair of angle members Hand-l6 are moufitedi-n superposed relationship to define thr 'btvvn aguide groove 15. A channel mem r H- is mounted intermediate track 12a and groove is and serves as a reinforcement and spacer.

An endless conveyor 20 is then mounted on the frame ill to move therearound in a generally rectangular path. Such conveyor may conveniently comprise. a pair of vertically spaced driving chains .2l'la. to which are secured: in spaced relationship a plurality of mounting plates 22. Each of the mounting plates 22 is provided with a pair of rollers 24 adjacent its top end thereof which respectively cooperate with the track lZa to provide guided support for the plate 22. In addition, a depending rib 22a. is secured to the bottom edge of the plate 22 which projects'into the guiding groove to restrain the plates 22 against lateral movements. The chains 28a are secured to the plates 22 by bracket members 22b formed on the rear side of such plates. Chains a are then driven at a constant speed around the rectangular periphery of the frame lfl-byany suitable form of driving mechanism (not shown),

On each of the plates 22, a bumper bar clamp- .ing device 30 is, provided. Such clamping device comprises a base 32 (Figures 4 and 5) which is secured to the plate 22 by suitablescrews 32a. A stationary jaw 34- is rigidly. secured to base 32 by screws 34a. .A hole 34 is provided in the stationary jaw 34 adjacent and parallel-to the base 32. The hole 34f slidably journals an actuating shaft 36 upon the end of which is adjustablymounted a movable clamp jaw 38. Such end of shaft 36 is threadedas indicated at 36a and movable clamp jaw 38 is provided with a and reclamped by the clamping device-30 in such reversed position, then when positioned in the notches 34c and 34d, as indicated by the dotted lines in Figure 5, the other arcuate end portion lc of the bumper bar will now be uppermost and will occupy substantially the same spatial position with respect to the conveyor 20 as did the arcuate end portion lb previously. Hence, the two pairs of notches or abutment surfaces provided on the fixed clamp jaw 34 completely compensate for the effect of non-concentric cross section of any bumper bar which is to be polished on the machine.

The. operation of the toggle latch mechanism will be clearly apparent to those skilled in the art. When the bell crank lever is in the position indicated by the solid lines in Figure 4 and abutting stop pin Me, the movable jaw 38 of suitable hole' to permit th threaded shaft end r portion 33:1 ,to be freely inserted therein. A pair of nuts 36b respectively disposed on opposite sides of movable clamp jaw 38 permit such jaw to be adjustably positioned on the end of Shaft 36.

I The other end of shaft 36 is bifurcated as indicated .at '36c and pivotally connected by a transversepin 36dto a link 31., Link 31 is in turnpivoted to the short arm 40a of a bell crank lever 40. The long arm 40b of suchlever is provided at its extremity with a manual operating handle 40c. Bell crank lever '40 is medially pivoted on a pin 43d 'which is suitably mounted in base plate 32. The pin 48d dispos'edin alignment with the axis of shaft 36 and hence the bell crank lever 49 and link 38 constitute an over center clamping toggle linkage for controllingfthepositioning of movable clamp jaw 38. 'Astop pin 40emay be provided to limit the movement of lever 40'.

r The fixed clampjaw-34 is provided with a pair pf abutment'members 34b which project generally toward the movable clamp'jaw 38. Each of such abutment "members isin turn provided with a notch .340 adjacent its outer end. The location of notches 340 is so arranged with respect to the configuratlon,'of the particular bumper bars which are'to b'e'ope'rated on by the machine so that"when'themedial portion In .01 a bumper bar I. is positioned as indicated by thefsolid lines in'Figure 5 with one edge thereofrestingfin the notch 34d defined by the junction of one of the abutment members 34b with the surface 34s of the fixed clamp 34 and the other edge resting'inthe notch 340 of the other abutment member, then one' arc uate end portion lb of the bumper bar l,jin this case the top end, will be disposed onjthe conveyor 20 in substan-- tial alignment'with the direction of movement of such conveyor. When the bum'per bar I is reversed end'for'endwith'respect to the conveyor the clamping device will be moved to its proximate position with respect to the fixed jaw 34. When bell crank lever 40 is manually shifted to the position indicated by the dotted lines in Figure 4, the movable clamp jaw 38 will bemoved to its remote position with respect to fixed clamp jaw 34 and hence a bumper bar I may be readily removed or inserted between such clamping jaws.

The clamping devices 30 are mounted on the conveyor support plates 22 in suitable angular relationship with respect thereto so that when a bumper bar I is engaged by the clamping device 30 on its central portion la, the top arcuate end portion lb of such bumper bar will be disposed in substantial alignment with the direction of movement of the conveyor 20. By substantial alignment, is meant that the convex exterior surface of such arcuate end portion lb lies on the average as closely as possible in a horizontal plane, it being appreciated of course that such surface being arcuate it cannot accurately be said to ever lie in a horizontal plane. However, it is believed that those skilled in the art will fully understand the foregoing definition of the manner in which the arcuate'end portions are disposed with respect to the direction of movement of the conveyor.

In such position, the concave surface of the arcuate end portion lb of each bumper bar I rests upon an arcuately shaped portion 42a of a supporting rod 42. Support rod 42 is rigidly secured to conveyor plate 22 by being inserted in a bracket 44 provided thereon.

It is therefore apparent that the bumper bars I, when loaded on the conveyor 28 at the loading position indicated in Figure 1 will pass along the long side of the rectangular path traversed by the conveyor 20 with the topmost arcuate portion lb disposed substantially parallel to the direction of movement. A plurality of polishing units 50 are provided in spaced relationship along this portion of the path of conveyor 20. Such polishing units comprise a base 50a, (Figure 3) which is suitably supported upon the horizontal frame members lllb, a vertically adjustable pedestal 50b, and a support head 50c swivelly adjustably mounted on the top of pedestal 5%. Support head 50c defines bearings 58d for supporting a polishing wheel shaft 50c. A polishing wheel 52 is conveniently secured to one'end-of shaft 50e while the other end carries a pulley 54 which is belt driven by a suitable electric motor 56 which is also supported on adjustable head 50c. It should be understood that the adjustable mounting of the polishing wheels may comprise any one of several well known forms and no claim is made to the details oj'such construction.

Each of the polishing wheels 52 may thus be adjustably positioned with respect to the path of movement of the successive arcuate end portions lb of the bumper bars I so as to engage a predetermined area of such arcuate end portions. While it is obvious that any desired number of polishing units 59 may be provided, we have de termined that completely satisfactory polishing may be accomplished by the provision of three polishing units 50 on each of the long sides of the rectangular path of conveyor 20.

Therefore, when each successive bumper bar I finishes the traverse of the initial long side of the rectangular path of the conveyor, the uppermost arcuate end portion lb will have been satisfactorily polished. Hence, as the bumper bar I traverses the short side of the rectangular conveyor path, a reversing station is provided. At this station, an operator releases each successive clamping device 30 and reverses the position of the bumper bars I end for end with respect to the conveyor 20. Each bumper bar I is then resecured on the conveyor by closing the clamping device 30. It will be noted that in this reversed position, the transverse edges of the bumper bar I engage a different pair of abutment surfaces on. the fixed clamp jaw as illustrated in Figure 5 and heretofore described in detail. Therefore, even though the cross sectional configuration of the particular bumper bar is non-concentric, the other arcuate end portion Ic, which is now uppermost, will occupy an identical spatial position with respect to the conveyor as did the other arcuate end portion Ib previously. Therefore, as the bumper bars I are carried down the second long side of the rectangular conveying path back toward the loading position, the polishing wheels 52 disposed along such path will effect an identical polishing operation upon the arcuate end portions Ic as was heretofore accomplished on the other arcuate end portions lb. As each successive bumper bar I completes the rectangular conveyor path, it is removed from the conveyor plate at the unloading station and at this point, both arcuate ends of the bumper bar will have been satisfactorily polished.

From the foregoing description, it is apparent that a machine embodying this invention permits the economical polishing of surfaces of members of irregularly shaped contours. As applied to the polishing of the arcuate end portions of bumper bars, the machine will rapidly produce a completely satisfactory polish on such end portions and requires attention of the operator only in the loading, unloading and reversing operations. Furthermore, the machine will impart a substantially identical polish to both ends of such bumper bars irrespective of the fact that the bumper bar may have a non-concentric cross sectional configuration.

It will, of course, be understood that various details of construction may be modified through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claim.

We claim as our invention:

In a machine for polishing an end of a bumper having a generally U-shaped cross-sectional configuration with one leg of the U shorter than the other, the combination of a conveyor and a clamp secured to said conveyor and arranged to clamp a bumper with an outer end extending beyond said conveyor, said clamp having a first clamping member with a base and spaced arms extending away from the base and having opposed shoulders spaced from said base and a second clamping member movable against the outer surface of the bumper, each shoulder being arranged to receive the edge at the end of the short leg of the U-shaped bumper when the edge at the long end abuts the base of said first clamping member, said shoulders thereby defining tw alternate clamping positions in each of .which the outer end of the bumper occupies an identical spatial position relative to said conveyor.

THOMAS E. ROBINSON. FRANK H. HARTLEP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,544,185 Schnell June 30', 1925 2,013,196 Woolens Sept. 3,1935 

